LES evaluation of the aerodynamic characteristics of high-rise building with horizontal ribs under atmospheric boundary layer flow

Abstract

The façade ribs have shown good performance on mitigation of wind effect on high-rise building. In present paper, LES approach is used to evaluate the impact of horizontal ribs on flow field and wind force of high-rise building under atmospheric boundary layer flow. The results show that horizontal ribs obviously suppress the formation of the separation vortex near sidewall and increase the vortex size in the near wake. The ribs can apparently inhibit the vertical flow near building façade, small recirculation is formed near the ribs and a focus is induced on the face in between every two adjacent ribs, which finally causes a considerable alteration of near-wall flow pattern. The variation of near-wall flow leads to a significant change of wind pressure distribution and wind force. It is found that horizontal ribs can cause “Zigzag” pattern of mean pressure along the altitude of building, and the ribs can reduce the fluctuating lift up to 27%. The continuous ribs show obvious effect on reducing the wind load through changing the near-wall flow, vortex structure and wind pressure distribution, and the discontinuous ribs shows relatively weak impact on the wind force.